Conventional trucks or trailers in the industry can include a loading ramp stored in a ramp carrier box mounted within the truck or trailer chassis. The ramp can be withdrawn from the carrier box to facilitate loading and unloading of cargo from the rear of the truck or trailer.
For example, Carty U.S. Pat. No. 4,929,018, discloses a truck chassis which provides storage space for a loading ramp between the longitudinal frame members of the chassis. The ramp is received between an opposing pair of angle brackets attached to the inner face of each frame member. During loading and unloading of cargo from the truck, the ramp is withdrawn from the storage area and the forward end of the ramp is set on the ground. The rear end of the ramp is then manually lifted upwardly and forwardly until a pair of hooks of the end of the ramp engage an upstanding portion of the truck body.
Similarly, Abromavage et al., U.S. Pat. No. 3,511,393, discloses a loading ramp for a truck wherein the rear end of the ramp is manually lifted upwardly and forwardly until a pair of hooks on the rear end of the ramp engage corresponding brackets on the rear of the truck bed.
Additionally, Sherry U.S. Pat. No. 2,370,427, discloses a portable ramp for vehicles that is stored between opposing frame members in the chassis of a truck. The rear end of the ramp includes a hooked end which is adapted to engage a pivotal angle bar mounted towards the front end of the storage area. As the ramp is withdrawn from the storage area, the hooked end engages the angle bar, which pivots upwardly to elevate the end of the ramp to substantially the floor height of the trailer.
These ramp storage arrangements, however, are not without drawbacks. For example, the Carty and Abromavage ramps must be manually lifted upwardly and forwardly until the ramp hooks engage a portion of the truck body. This manual lifting can cause fatigue or physical injury. Moreover, the dimensions of the ramp are limited by the amount of weight a typical person can safely lift. Additionally, the Sherry ramp requires structural changes to the floor of the vehicle, which limits the weight of the cargo that can be loaded into and unloaded from the vehicle.